Firstly, open the Apps in Windows 10. Otherwise, you can use the Programs & Features in Windows 7.
Then, select the right Microsoft Office product to repair and Modify.
Now, note whether your Word is a product key or an account-based product.
Online Repair and Repair options are available based on Click-to-run or MSI-based.
Finally, follow the on-screen instructions to finish the error rectification process.